Here are the numbers for 2016 domestic origin/destination for all our hubs from the DOT:

Chicago (all airports) 2,360,000
Houston (all airports) 1,109,000
New York (all airports)= 3,391,000
Wash DC (all airports)= 2,116,000
Cle = 418,000
Denver = 1,563,000
LA (all airports)= 3,168,000
SFO (all airports)= 2,483,000

https://www.transtats.bts.gov/Oneway...d=&sort_order=